Kinematic-Synergy-Based Robotic Feedback Promotes Short-Term Retention of Altered Human Bimanual Motor Behavior

Area of Science:

• Human-centered robotics
• Motor control and learning
• Rehabilitation engineering

Background:

• Robotic interventions can improve motor performance, but adapted motor patterns often wash out.
• Retention of motor improvements is crucial for effective robotic-assisted training.
• Existing methods for robotic intervention have limitations in complex, multi-objective tasks.

Purpose of the Study:

• To investigate a novel kinematic-synergy-based torque feedback method for improving motor pattern retention in bimanual tasks.
• To determine if targeting kinematic synergies can enhance short-term retention of motor adaptations.
• To evaluate the effectiveness of this method for multi-objective, bimanual tasks relevant to rehabilitation and training.

Main Methods:

• Participants performed two multi-objective, bimanual tasks using an exoskeleton.
• Kinematic synergy adaptation was assessed using synergy-dependent torque feedback versus a velocity-dependent force field.
• Intrasubject Pearson's correlation coefficient of primary synergies was used to test hypotheses.

Main Results:

• Robotically augmented system dynamics induced adaptation in kinematic synergies (p < 0.05).
• Motor pattern washout occurred upon removal of the robotic system.
• Targeting kinematic synergies resulted in significant short-term retention of altered motor patterns (p = 0.04).

Conclusions:

• Kinematic synergy adaptation occurs in response to augmented system dynamics.
• Synergy-dependent torque feedback shows promise for achieving short-term retention of motor adaptations.
• This approach has positive implications for long-term motor training and rehabilitation using robotic systems.